Chap 3 Drainage Question & Answers Class 9 Geography

Chap 3 Drainage Question & Answers Class 9 Geography: Find here The answers to intext-questions and the chapter ‘Drainage’ exercise questions. Click here for more study resources.

Intext-Questions & Answers

The intext part contains some as titled ‘Do you know?’ and some as ‘Find out’. Here are compiled both the types with explanations to ‘Do you know?’ section and answers to ‘Find out’ section.

Do you know?

1. The world’s largest drainage basin is of the Amazon river

Explanation: The Amazon River has the world’s largest drainage basin. The Amazon River basin, also known as the Amazon Basin or the Amazon Watershed, is the area of land drained by the Amazon River and its tributaries. It covers a vast expanse of South America, including parts of Brazil, Peru, Colombia, Venezuela, Ecuador, Bolivia, and Guyana.

The Amazon River itself is the second-longest river in the world (after the Nile) and is known for its immense volume of water and its crucial role in the world’s hydrological cycle and biodiversity. The Amazon Basin is home to a diverse range of plant and animal species and contains a significant portion of the world’s rainforests.

The Amazon River and its basin play a vital role in global climate regulation, as well as being a critical habitat for numerous species and a source of livelihood for many indigenous communities.

2. According to the regulations of the Indus Water Treaty (1960), India can use only 20 per cent of the total water carried by the Indus river system. This water is used for irrigation in Punjab, Haryana and the southern and the western parts of Rajasthan.

Explanation: The Indus Waters Treaty of 1960 is indeed a significant international agreement that governs the sharing of the waters of the Indus River system between India and Pakistan. The treaty was brokered by the World Bank and has been in place for decades.

Under the terms of the treaty:

  • The Indus Basin: The treaty divides the Indus River system into two main “eastern” rivers (the Sutlej, Beas, and Ravi) and three main “western” rivers (the Indus, Jhelum, and Chenab). India has control over the eastern rivers, while Pakistan has control over the western rivers.
  • Water Allocation: India is allocated the use of 20% of the total water carried by the Indus River system, mainly for irrigation purposes in the Indian states of Punjab, Haryana, and parts of Rajasthan. Pakistan receives the bulk of the water, primarily for its agriculture in the Indus Plains.
  • Transparency and Data Sharing: The treaty establishes a mechanism for the exchange of data and information on river flows between the two countries. This transparency is crucial for managing the shared water resources.
  • Dispute Resolution: The treaty also provides for dispute resolution mechanisms in case conflicts or disagreements arise between the two countries regarding the sharing of water resources.

The Indus Waters Treaty has generally been regarded as one of the more successful water-sharing agreements in the world and has contributed to the peaceful coexistence of India and Pakistan despite other tensions. It has played a crucial role in managing and allocating water resources in a region heavily dependent on agriculture.

3. The Sundarban Delta derived its name from the Sundari tree, which grows well in marshland. It is the world’s largest and fastest growing delta. It is also the home of Royal Bengal tiger.


  • Sundari Trees: The Sundarbans Delta, located in the Bay of Bengal, derives its name from the “Sundari” tree (Heritiera fomes), which is one of the dominant tree species in the region. These trees thrive in the marshy terrain of the delta.
  • World’s Largest Delta: The Sundarbans is indeed the world’s largest delta, and it is characterized by its intricate network of waterways, mangrove forests, and estuaries. It spans across India and Bangladesh and is known for its unique and fragile ecosystem.
  • Royal Bengal Tiger: The Sundarbans Delta is famous for being the habitat of the Royal Bengal Tiger (Panthera tigris tigris). This region is home to one of the largest populations of Bengal tigers in the world. Due to its unique environment, these tigers are known for their ability to swim and adapt to a watery habitat.

The Sundarbans Delta is not only ecologically important but also culturally significant, and it has been designated as a UNESCO World Heritage Site to protect its biodiversity and preserve its unique ecosystem.

4. The Namami Gange Programme is an Integrated Conservation Mission approved as a ‘flagship programme’ by the Union Government in June 2014 to accomplish the twin objectives of effective abatement of pollution, conservation and rejuvenation of the national river, Ganga. You may explore about this project at NamamiGanga.sspx

Explanation: The Namami Gange Programme, also known as the “National Mission for Clean Ganga (NMCG),” is an integrated conservation mission aimed at the effective abatement of pollution, conservation, and rejuvenation of the Ganga River, one of India’s most sacred and iconic rivers. The program was approved as a flagship program by the Indian government in June 2014. It is a comprehensive and ambitious initiative aimed at cleaning and restoring the Ganga to its pristine state.

Key features and objectives of the Namami Gange Programme include:

  • Pollution Abatement: The program focuses on reducing pollution in the Ganga River by implementing sewage and industrial effluent treatment plants, controlling non-point source pollution, and promoting sustainable sanitation practices.
  • Conservation of River Ganga: The program aims to conserve the Ganga’s unique biodiversity and its associated ecosystems, such as wetlands and floodplains.
  • Rejuvenation: Efforts are made to rejuvenate the river by maintaining minimum environmental flows, restoring and protecting ghats (riverbanks), and promoting afforestation along the river.
  • Wastewater Management: The program emphasizes wastewater management in towns and cities along the Ganga’s banks to prevent untreated sewage from entering the river.
  • Public Awareness and Participation: Public participation and awareness campaigns are an integral part of the program to engage communities and stakeholders in Ganga conservation efforts.
  • Innovative Financing: The program explores innovative financing mechanisms to support Ganga conservation projects, including public-private partnerships.
  • International Collaboration: The program seeks collaboration with international organizations and governments to benefit from global expertise and resources in river conservation.

The Namami Gange Program is implemented by the National Mission for Clean Ganga (NMCG) under the Ministry of Jal Shakti, Government of India. It is a significant initiative to restore and protect the Ganga River and its associated ecosystems, which have immense cultural, ecological, and economic importance in India.

For more detailed information and updates about the Namami Gange Program, you can visit the official website at

5. Brahmaputra is known as the Tsang Po in Tibet and Jamuna in Bangladesh.

Explanation: The Brahmaputra River is known by different names in different regions through which it flows. Here are some of its names:

  • Tsang Po (or Yarlung Tsangpo): In Tibet, the Brahmaputra is known as the “Tsang Po” or “Yarlung Tsangpo.” It originates from the Tibet Autonomous Region of China.
  • Brahmaputra: After crossing into India from Tibet, it is known as the Brahmaputra River. In India, it flows through the states of Arunachal Pradesh and Assam.
  • Jamuna (or Yamuna): In Bangladesh, the Brahmaputra River is known as the “Jamuna.” The Jamuna is one of the major rivers in Bangladesh and merges with the Ganges (known as the Padma in Bangladesh) to form the world’s largest delta, the Sundarbans Delta.

The Brahmaputra River plays a crucial role in the geography, culture, and ecology of the regions it traverses, from its source in Tibet to its delta in Bangladesh.

6. The Narmada river conservation mission has been undertaken by the government of Madhya Pradesh by a scheme named Namami Devi Narmade. You may visit their website. to learn more about it.

Explanation: The Narmada River conservation mission, known as “Namami Devi Narmade,” is an initiative undertaken by the government of Madhya Pradesh to protect and rejuvenate the Narmada River, one of the major rivers in central India. The program aims to ensure the sustainable development and conservation of the Narmada River and its associated ecosystems.

For more detailed information about the “Namami Devi Narmade” program and its various components, you can visit the official website at

Such initiatives are critical for the preservation and sustainable management of rivers, which are essential natural resources for the regions they flow through.

7. The river Kaveri makes the second biggest waterfall in India, known as Shivasamudram Falls. The hydroelectric power generated from the falls is supplied to Mysuru, Bengaluru and the Kolar Gold Field.

Explanation: The Shivasamudram Falls on the river Kaveri are indeed one of the most prominent waterfalls in India. These falls are located in the Mandya district of Karnataka and are known for their natural beauty and the hydroelectric power generation they support.

Key points about Shivasamudram Falls:

  • Location: Shivasamudram Falls are located on the Kaveri River, approximately 133 kilometers (83 miles) east of the city of Bangalore (Bengaluru) in Karnataka.
  • Hydroelectric Power: The falls have been harnessed for hydroelectric power generation, which plays a significant role in supplying electricity to various regions, including Mysuru, Bengaluru, and the Kolar Gold Fields. The power generated at these falls has contributed to the region’s energy needs.
  • Waterfall Types: Shivasamudram Falls are divided into two main sections, known as the “Gaganachukki Falls” and the “Bharachukki Falls.” The Gaganachukki Falls are more popular and are known for their impressive cascading waterfalls.
  • Tourist Attraction: Apart from their role in hydroelectric power generation, Shivasamudram Falls are also a popular tourist attraction. Visitors are drawn to the natural beauty of the falls and the surrounding landscape.
  • Wildlife Sanctuary: The area around the falls is part of the Cauvery Wildlife Sanctuary, which is home to various species of wildlife and offers opportunities for nature enthusiasts and wildlife lovers.

Overall, Shivasamudram Falls are not only a source of hydroelectric power but also a natural wonder and a destination for tourists and nature enthusiasts.

8. 71 per cent of the world’s surface is covered with water, but 97 per cent of that is salt water. Of the 3 per cent that is available as freshwater, three quarters of it is trapped as ice.

Explanation: The above context of water distribution is explained below

  1. Global Water Coverage: Approximately 71% of the Earth’s surface is covered by water, making it a predominant feature of our planet.
  2. Saltwater vs. Freshwater: Of the total water on Earth, about 97% is saltwater found in the world’s oceans and seas. This saltwater is not suitable for most human uses, including drinking and irrigation.
  3. Availability of Freshwater: Only about 3% of Earth’s water is freshwater, which is essential for human and terrestrial life. However, of this freshwater, a significant portion is not readily accessible for human use.
  4. Frozen Freshwater: A substantial part of the available freshwater is trapped as ice in glaciers, polar ice caps, and mountain regions. This frozen freshwater represents a significant portion of the Earth’s freshwater resources but is not easily usable.
  5. Liquid Freshwater: The remaining portion of freshwater exists in liquid form, primarily in rivers, lakes, groundwater, and in the form of atmospheric water vapor.

These facts highlight the importance of responsible water management and conservation, as freshwater resources are limited and crucial for various human activities, including agriculture, industry, and daily life.

Find out

1. Which river has the largest basin in India?

Ans. The Ganga River has the largest basin in India. The Ganga Basin is one of the largest river basins in the world, covering a vast geographical area in northern India. It is known for its extensive network of tributaries and plays a significant role in the country’s geography, culture, and economy.

2. Lakes of large extent are called seas, like the Caspian, the Dead and the Aral seas.

Ans. Lakes of large extent that are often referred to as “seas” are known as “inland seas” or “closed seas.” These bodies of water share some characteristics with both lakes and seas. While they are technically landlocked lakes, they are often so large that they resemble seas in terms of their size, depth, and the extent of their shores.

The Caspian Sea, the Dead Sea, and the Aral Sea are examples of such inland seas:

  1. Caspian Sea: The Caspian Sea is the largest inland sea in the world. It is located between Europe and Asia and is bordered by several countries, including Russia, Kazakhstan, Turkmenistan, Iran, and Azerbaijan. It is often referred to as a sea due to its large size, but it is, in fact, a saltwater lake.
  2. Dead Sea: The Dead Sea is a saltwater lake located between Jordan and Israel. It is known for its extremely high salt content, which makes it one of the saltiest bodies of water on Earth. The Dead Sea is often called a sea because of its historical significance and size.
  3. Aral Sea: The Aral Sea, located in Central Asia, was once one of the world’s largest lakes. However, due to extensive irrigation practices and water diversion, it has significantly shrunk in size over the years. It was historically referred to as a sea due to its size and salinity.

These “seas” are unique in that they are landlocked and have no outlet to the world’s oceans, which distinguishes them from typical seas. Their large size and high salinity levels have earned them the designation of “inland seas.”

3. The name of the biggest waterfall in India.

Ans. The biggest waterfall in India is the “Jog Falls,” also known as the “Gerosoppa Falls” or “Joga Falls.” It is located in the Shimoga District of the Indian state of Karnataka. Jog Falls is one of the most famous and tallest waterfalls in India, and it is created by the Sharavathi River, which drops from a height of about 253 meters (830 feet) in a single unbroken plunge.

Jog Falls is a spectacular natural attraction and a popular tourist destination, drawing visitors from across India and around the world. The best time to witness the waterfall in its full glory is during the monsoon season when the Sharavathi River is at its peak flow.

Textbook Exercise Questions & Answers

1. Choose the right answer from the four alternatives given below.

(i) In which of the following states is the Wular lake located?

(a) Rajasthan (c) Punjab (b) Uttar Pradesh (d) Jammu and Kashmir

Answer: (d) Jammu and Kashmir

(ii) The river Narmada has its source at
(a) Satpura (c) Amarkantak
(b) Brahmagiri (d) Slopes of the Western Ghats

Answer: (c) Amarkantak

(iii) Which one of the following lakes is a salt water lake?
(a) Sambhar (c) Wular
(b) Dal (d) Gobind Sagar

Answer: (a) Sambhar

(iv) Which one of the following is the longest river of the Peninsular India?
(a) Narmada (c) Godavari
(b) Krishna (d) Mahanadi

Answer: (c) Godavari

(v) Which one amongst the following rivers flows through a rift valley?
(a) Mahanadi (c) Krishna
(b) Tungabhadra (d) Tapi

Answer: (d) Tapi

2. Answer the following questions briefly.

(i) What is meant by a water divide? Give an example.

Answer: A water divide is an elevated geographical feature such as a mountain or ridge that separates two drainage basins or river systems. An example is the Western Ghats, which serves as a water divide in Peninsular India.

(ii) Which is the largest river basin in India?

Answer: The Ganga Basin is the largest river basin in India.

(iii) Where do the rivers Indus and Ganga have their origin?

Answer: The Indus River originates in Tibet near Lake Mansarowar, while the Ganga River has its source in the Gangotri Glacier in the Himalayas.

(iv) Name the two headstreams of the Ganga. Where do they meet to form the Ganga?

Answer: The two headstreams of the Ganga are the Bhagirathi and the Alaknanda. They meet at Devaprayag in Uttarakhand to form the Ganga.

(v) Why does the Brahmaputra in its Tibetan part have less silt, despite a longer course?

Answer: The Brahmaputra in its Tibetan part has less silt because it flows through a cold and dry region with less vegetation, limiting the amount of eroded material it carries.

(vi) Which two Peninsular rivers flow through a trough?

Answer: The Narmada and the Tapi are two Peninsular rivers that flow through troughs.

(vii) State some economic benefits of rivers and lakes.

Answer: Economic benefits of rivers and lakes include irrigation for agriculture, transportation of goods and people, hydropower generation, tourism, and recreational activities.

3. Below are given names of a few lakes of India. Group them under two categories – natural and created by human beings.

(a) Wular (b) Dal (c) Nainital (d) Bhimtal (e) Gobind Sagar (f) Loktak (g) Barapani (h) Chilika (i) Sambhar (j) Rana Pratap Sagar (k) Nizam Sagar (l) Pulicat (m) Nagarjuna Sagar (n) Hirakund

Answer: The groups of natural and man-made lakes are given below.

Natural Lakes:

  • Wular
  • Dal
  • Nainital
  • Chilika

Lakes Created by Human Beings:

  • Gobind Sagar
  • Barapani
  • Rana Pratap Sagar
  • Nizam Sagar
  • Nagarjuna Sagar
  • Hirakund

4. Discuss the significant difference between the Himalayan and the Peninsular rivers.

Answer: The differences between the Himalayan and the Peninsular rivers are explained below.

Himalayan Rivers:

  • Himalayan rivers are primarily perennial, meaning they have water throughout the year.
  • They originate from glaciers and high mountain ranges.
  • These rivers have long courses and carry a significant load of silt and sand.
  • They exhibit intensive erosional activity in their upper courses and create features like gorges.
  • Himalayan rivers form well-developed deltas in their lower courses.

Peninsular Rivers:

  • Peninsular rivers include both perennial and seasonal rivers.
  • They have shorter and shallower courses compared to Himalayan rivers.
  • Peninsular rivers are more dependent on rainfall, and their flow can significantly reduce during dry seasons.
  • They originate from the central highlands or the Western Ghats.
  • Some Peninsular rivers flow through troughs and have a different geological origin.

Differences in tabular form:

CharacteristicHimalayan RiversPeninsular Rivers
(i) Flow TypePerennial (rainfall and snowmelt)Seasonal (rainfall-dependent)
(ii) Course LengthLonger coursesShorter and shallower courses
(iii) Geological ActivitiesIntensive activities, create features like gorges, oxbow lakes, meanders, etc.Do not form meanders or oxbow lakes
(iv) Flow TerrainFlow in levelled northern plainsFlow over uneven rocky surfaces
Useful for irrigation and navigationNot useful for irrigation and navigation
(v) Alluvium DepositionDeposit fertile alluvium in Indo-Gangetic plainsSwift current, limited alluvium deposit
(vi) Groundwater RechargePorous soil absorbs water,Rocky soil does not absorb water,
used as groundwater by digging wells and tubewellsdigging wells not possible
(vii) ExamplesGanga, Yamuna, Ghagra, Gandak, Kosi, etc.Mahanadi, Godavari, Krishna, Kaveri, Narmada, Tapi, etc.

5. Compare the east flowing and the west flowing rivers of the Peninsular plateau.

Answer: The comparison between the east flowing and the west flowing rivers of the Peninsular plateau

East Flowing Rivers:

  • East flowing rivers on the Peninsular plateau flow towards the Bay of Bengal.
  • They include rivers like the Godavari, Krishna, Mahanadi, and Kaveri.
  • These rivers are generally longer and have a larger drainage basin.
  • They receive water from the Western Ghats and provide water for irrigation and agriculture in the eastern plains.

West Flowing Rivers:

  • West flowing rivers on the Peninsular plateau flow towards the Arabian Sea.
  • The Narmada and the Tapi are examples of west flowing rivers.
  • These rivers are shorter in length and have smaller drainage basins.
  • They originate in the central highlands and flow westward.

6. Why are rivers important for the country’s economy?

Answer: Rivers are important for the country’s economy for several reasons:

  • They provide water for irrigation, supporting agriculture, which is a major source of livelihood in India.
  • Rivers serve as natural transportation routes, facilitating the movement of goods and people, contributing to trade and commerce.
  • Hydropower generation from rivers adds to the country’s energy production.
  • Rivers moderate local climates and support aquatic ecosystems.
  • They enhance the natural beauty of regions, attracting tourism and recreational activities, which generate revenue.

Map Skills

(i) On an outline map of India mark and label the following rivers:

Ganga, Satluj, Damodar, Krishna, Narmada, Tapi, Mahanadi, and Brahmaputra.

(ii) On an outline map of India mark and label the following lakes:

Chilika, Sambhar, Wular, Pulicat, Kolleru.

Answer: The map work is given below

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